This invention relates generally to the art of printing and more particularly to the art of measuring the printability of a substrate.
In the art of printing, it has been known that the ability of a substrate surface to receive and retain print media is related to the surface tension of that substrate. This degree of surface tension can be measured in relative terms by the placement of a drop of liquid upon that surface while in the horizontal state. The surface with the drop of liquid thereon is then rotated until the drop of liquid begins to run. The angle of rotation is proportional to the surface tension of the substrate surface and thus indicative of the ability of that surface to receive and retain a printing medium. A substrate with a high surface tension receives and retains a printing medium better than a substrate with a lower surface tension.
Various prior art attempts have been made to quantify surface tension. Such efforts have normally involved the use of an electric motor to tilt a horizontal surface with an operator having the ability to deactivate the supply of electricity to the electric motor when a drop of liquid runs on the horizontal surface. After deactivating the electric motor, the angle of the surface is then measured.
The prior art process has suffered from the disadvantages of lack of reproduceability and a lack of standardization.